title: Capturing the lost phosphorus.
abstract: Minable phosphorus (P) reserves are being depleted and will need to be replaced by recovering P that currently is lost from the agricultural system, causing water-quality problems. The largest two flows of lost P are in agricultural runoff and erosion (∼46% of mined P globally) and animal wastes (∼40%). These flows are quite distinct. Runoff has a very high volumetric flow rate, but a low P concentration; animal wastes have low flow rates, but a high P concentration together with a high concentration of organic material. Recovering the lost P in animal wastes is technically and economically more tractable, and it is the focus for this review of promising P-capture technologies. P capture requires that organic P be transformed into inorganic P (phosphate). For high-strength animal wastes, P release can be accomplished in tandem with anaerobic treatment that converts the energy value in the organic matter to CH(4), H(2), or electricity. Once present as phosphate, the P can be captured in a reusable form by four approaches. Most well developed is precipitation as magnesium or calcium solids. Less developed, but promising are adsorption to iron-based adsorbents, ion exchange to phosphate-selective solids, and uptake by photosynthetic microorganisms or P-selective proteins.
authors.affiliation: Swette Center for Environmental Biotechnology, Biodesign Institute at Arizona State University, PO Box 875701, Tempe, AZ 85287-5701, USA. Rittmann@asu.edu
authors.forename: Bruce E
authors.initials: BE
authors.lastname: Rittmann
authors.forename: Brooke
authors.initials: B
authors.lastname: Mayer
authors.forename: Paul
authors.initials: P
authors.lastname: Westerhoff
authors.forename: Mark
authors.initials: M
authors.lastname: Edwards
mesh_terms: D003247:Conservation of Natural Resources / Q000379:methods*; D055669:Ecological and Environmental Phenomena; D005308:Fertilizers / Q000706:statistics & numerical data; D009943:Organophosphorus Compounds / Q000032:analysis; D010758:Phosphorus / Q000032:analysis*
chemical_list: D005308:Fertilizers; D009943:Organophosphorus Compounds; D010758:Phosphorus